During a printing process, when a paper passes through printing units, various ink colors are applied. Often the paper or plates applying the ink can shift resulting in improper alignment among two or more objects. The improper alignment results in gaps, which become prominent when two or more objects with contrasting colors abut. The appearance of gaps is called misregistration. Trapping is a process of compensating for misregistration on the printing units by printing small areas of overlapping colors where objects meet. Trapping helps in minimizing the gaps.
Trapping for objects such as text is performed differently by applying different rules as compared to the rules applied to line arts such as stroke. Often the stroke is used around the text to make the text appear bold. The stroke gels with the text to make the text and the stroke appear as a combination object. However, trapping rules for the text differ from trapping rules for the stroke resulting in an unpleasant appearance of the combination object when trapped. For example, FIG. 1 illustrates a trapped combination object 115 which is a combination of a trapped text (letter “B”) and a trapped stroke (not distinguishable as text and stroke are in same color). Traps 110a, 110b and 110c have thick width resulting in an unpleasant appearance. Further, traps 110b and 110c present at inner side of combination object 115 spread over background 105 and affect the overall appearance.
In light of the foregoing discussion, there is a need for an efficient technique for trapping objects.